Process to make olefins and aromatics from organics

ABSTRACT

The present invention relates to a process to make light olefins and aromatics, in a combined XTO-OC process, from an oxygen-containing, halogenide-containing or sulphur-containing organic feedstock comprising:
     a0) providing a first portion and a second portion of said oxygen-containing, halogenide-containing or sulphur-containing organic feedstock,   a) providing a catalyst comprising zeolitic molecular sieves containing at least 10 membered ring pore openings or larger in their microporous structure,   b) providing an XTO reaction zone, an OC reaction zone and a catalyst regeneration zone, said catalyst circulating in the three zones, such that at least a portion of the regenerated catalyst is passed to the 00 reaction zone, at least a portion of the catalyst in the 00 reaction zone is passed to the XTO reaction zone and at least a portion of the catalyst in the XTO reaction zone is passed to the regeneration zone;   c) contacting the first portion of said oxygen-containing, halogenide-containing or sulphur-containing organic feedstock in the XTO reactor with the catalyst at conditions effective to convert at least a portion of the feedstock to form a XTO reactor effluent comprising light olefins and a heavy hydrocarbon fraction;   d) separating said light olefins from said heavy hydrocarbon fraction;   e) contacting said heavy hydrocarbon fraction and the second portion of said oxygen-containing, halogenide-containing or sulphur-containing organic feedstock in the OC reactor with the catalyst at conditions effective to convert at least a portion of said heavy hydrocarbon fraction and oxygen-containing, halogenide-containing or sulphur-containing organic feedstock to light olefins and aromatics.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.13/000,401, filed on Mar. 14, 2011, which a national stage entry ofPCT/EP2009/057889, filed on Jun. 24, 2009, which claims priority from EP09154234.0, filed on Mar. 3, 2009, EP 09154232.4, filed on Mar. 3, 2009,and EP 08158924.4 filed on Jun. 25, 2008.

FIELD OF THE INVENTION

The present invention relates to a process to make olefins and aromaticsfrom heteroatomic organics and more precisely an XTO (organics toolefins) process combined with an OC (olefins conversion) process,producing aromatics and olefins comprising a catalyst regeneration zoneand such that at least a portion of the regenerated catalyst is passedto the OC reaction zone and at least a portion of the catalyst in the OCreaction zone is passed to the XTO reaction zone. A part of the organics(X-containing compound) is optionally sent to the OC reaction zone andthe remaining part to the XTO reaction zone.

The limited supply and increasing cost of crude oil has prompted thesearch for alternative processes for producing hydrocarbon products. Onesuch process is the conversion of oxygen-containing (by way of examplemethanol), halogenide-containing or sulphur-containing organic compoundsto hydrocarbons and especially light olefins (by light olefins is meantC₂ to C₄ olefins) or gasoline and aromatics. In the present applicationsaid oxygen-containing, halogenide-containing or sulphur-containingorganic compounds are also referred as “X”. In the present applicationthe conversion of said oxygen-containing (also referred as oxygenates),halogenide-containing or sulphur-containing organic compounds tohydrocarbons and especially light olefins is referred as XTO process.The interest in the XTO process is based on the fact that feedstocks,especially methanol can be obtained from coal, hydrocarbon residu's,biomass, organic waste or natural gas by the production of synthesisgas, which is then processed to produce methanol. The XTO process can becombined with an OC (olefins conversion) process to increase productionof aromatics and olefins. The XTO process produces light olefins such asethylene and propylene as well as heavy hydrocarbons such as butenes andabove. These heavy hydrocarbons are converted in an OC process to givemainly aromatics and additional ethylene and propylene. The XTO processis also known as MTO in case of methanol (methanol to olefins) process.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 7,132,581 concerns processes for converting oxygenates toolefins that include a step of pretreating catalyst used in theconversion reaction. A fresh or regenerated metalloaluminophosphatemolecular sieve, which is low in carbon content, is pretreated with analdehyde. The aldehyde forms a hydrocarbon co-catalyst within the porestructure of the molecular sieve, and the pretreated molecular sievecontaining the co-catalyst is used to convert oxygenate to an olefinproduct.

U.S. Pat. No. 7,057,083 relates to processes for converting oxygenatesto olefins that include a step of pretreating molecular sieve used inthe conversion reaction with a C4-C7 olefin composition, which containsone or more C4-C7 olefins. Fresh or regenerated molecular sieve, whichis low in carbon content, is contacted or pretreated with the olefincomposition to form a hydrocarbon co-catalyst within the pore structureof the molecular sieve, and the pretreated molecular sieve containingthe co-catalyst is used to convert oxygenate to a lighter olefinproduct.

U.S. Pat. No. 6,844,476 describes a method for converting heavy olefinspresent in a product stream exiting a first reaction zone into lightolefins and carbonaceous deposits on a catalyst without separation ofthe heavy olefins from the product stream exiting the first reactionzone. The method comprises creating the product stream exiting the firstreaction zone, the product stream exiting the first reaction zonecomprising the heavy olefins, moving the product stream exiting thefirst reaction zone to a second reaction zone without separation of theheavy olefins from the product stream exiting the first reaction zone,and contacting the product stream exiting the first reaction zone withthe catalyst under conditions effective to form the light olefins, thecontacting causing the carbonaceous deposits to form on at least aportion of the catalyst.

US20060161035 describes the average propylene cycle yield of anoxygenate to propylene (OTP) process using a dual-function oxygenateconversion catalyst is substantially enhanced by the use of acombination of:

1) moving bed reactor technology in the catalytic OTP reaction step inlieu of the fixed bed technology of the prior art;

2) a separate heavy olefin interconversion step using moving bedtechnology and operating at an inlet temperature at least 15° C. higherthan the maximum temperature utilized in the OTP reaction step;

3) C2 olefin recycle to the OTP reaction step; and

4) a catalyst on-stream cycle time of 700 hours or less. Theseprovisions hold the build-up of coke deposits on the catalyst to a levelwhich does not substantially degrade dual-function catalyst activity,oxygenate conversion and propylene selectivity, thereby enablingmaintenance of average propylene cycle yield for each cycle near or atessentially start-of-cycle levels.

U.S. Pat. No. 5,914,433 relates to a process for the production of lightolefins comprising olefins having from 2 to 4 carbon atoms per moleculefrom an oxygenate feedstock. The process comprises passing the oxygenatefeedstock to an oxygenate conversion zone containing a metalaluminophosphate catalyst to produce a light olefin stream. A propylenestream and/or mixed butylene is fractionated from said light olefinstream and butylenes and heavies cracked to enhance the yield ofethylene and propylene products. This combination of light olefinproduct and butylene and heavies cracking in a riser cracking zone or aseparate cracking zone provides flexibility to the process whichovercomes the equilibrium limitations of the aluminophosphate catalyst.In addition, the invention provides the advantage of extended catalystlife and greater catalyst stability in the oxygenate conversion zone. Insaid process the effluent of the riser cracking zone or the separatecracking zone is sent to the oxygenate conversion zone.

It has now been discovered a more efficient process to make lightolefins, in particular propylene and aromatics from oxygenates. Thisinvention relates to a process including three zones: a XTO reactionzone containing catalyst wherein “X” (e.g. oxygenates) are convertedinto mainly light olefins, an OC reaction zone containing substantiallythe same catalyst wherein heavier olefins and optionally ethylene areconverted into aromatics and additional light olefins and a zone whereinthe catalyst used in the other two zones is regenerated (the catalystregeneration zone also referrered as the regeneration zone). Thisinvention relates to processes for converting oxygenates to olefins overa zeolite-based catalyst (in the XTO reaction zone) that include a stepof primarily using the zeolite-based catalyst in the conversion reaction(the OC reaction zone) with a substantially olefinic feedstock, whichcontains one or more C₂-C₁₂ olefins, and forming by way of example 0.1wt % or more of coke-like deposition on the molecular sieves. The mainrole of this hydrocarbons deposition is in selective deactivation of thenon-selective acid sites. This contact of the molecular sieve with anolefinic feedstock could be performed in the presence or in absence ofwater and oxygenated compounds. In a most preferred embodiment, thiscontact is performed in the absence of water and oxygenated compounds.It was found that the primarily use (as a pre-treatment) ofzeolite-based catalyst for the conversion of olefinic feedstock in theOC reaction zone provides a catalyst with significantly improvedcatalyst performance for the MTO reaction in the XTO reaction zone.Without willing to be bound to any theory, it is believed that theeffect consists in a selective poisoning of the non-selective acid sitesat the external surface which are responsible typically forside-reaction, resulting in enhanced formation of paraffins. In thepresent invention we are talking about selectively pre-deactivatedcatalyst in which the deposited coke has no catalytic activity as is inthe case of coke co-catalyst on SAPO-type materials.

Another advantage in using the olefin compositions of this invention forthe primarily use of zeolite-based catalyst is that this provides a wayto reduce undesirable by-products in the overall conversion ofoxygenates to olefins. Typically, heavier olefins such as the C₄-C₇olefins are considered as undesirable by-products, because the value ofthose olefins are considerably lower than ethylene and propylene.Therefore, the by-products of the oxygenate to olefins reaction processcan be used to enhance selectivity of the catalyst to provide aromaticsand the more desirable ethylene and propylene products.

Advantages of the present invention:

-   -   Perform the reaction in each operating zone under optimal        conditions    -   Optimal catalyst selectivity by primarily use of the catalyst        for olefin cracking    -   Better heat integration between the different reactor zones

It is preferred that the catalyst in the three zones is in the fluidisedstate. This allows easy transport of catalyst from one zone to otherzones.

The conversion of X is carried out in a separate zone than theconversion of ethylene or C4-C7 hydrocarbons. This allows optimisingeach reaction conditions separately. The conversion of X is a stronglyexothermic conversion and is hence best performed in a fluidised bedwith substantially homogenous temperature throughout the catalyst bed,wherein the temperature is regulated by injecting the feed at atemperature lower than the reaction temperature (cold feed serves asheat sink) or by cooling the catalyst by means of a catalyst cooler byraising steam in a heat exchanger. The conversion of C4-C7 olefins is onthe contrary an endothermic or slightly exothermic reaction. The heat ofreaction can be provided by super-heating the feedstock so that theoutlet temperature of the reactor is sufficiently high to obtain asufficiently high conversion of the feedstock. The heat of reaction canalso be provided by means of a high catalyst circulation rate atsufficiently high temperature to convert the feedstock. This can easilybe done in a fluidised bed reactor with catalyst injection at the bottomof the reactor (inlet) with catalyst separation at the top of thereactor (outlet). Sufficiently hot catalyst can come from theregenerator where by combustion of coke deposited on the catalyst withair in a controlled manner. In order to maximise combustion rate andminimise the combustion temperature, combustion promoters are added,known by the persons in the art. The combustion promoters consist ofplatinum on alumina carriers. In case not enough coke is depositedduring conversion of X or of C4-C7 olefins, additional fuel can beinjected in the regenerator to provide heat to heat up more catalyst sothat more heat can flow to the C4-C7 conversion zone. Examples ofadditional fuel are natural gas, LPG, heating oil or synthesis gas. Inparticular CO-rich synthesis gas is suitable. This CO-enriched synthesisgas is readily available in a methanol synthesis plant as for instancethe purge stream of the methanol synthesis reactor loop.

Another source of hot catalyst is the XTO reactor zone as the conversionof X is strongly exothermic. The temperature of the catalyst, leavingthe XTO zone should be at least higher than the temperature required atthe outlet of the C4-C7 olefin conversion zone in order to obtainsufficient conversion. The conversion of C4-C7 olefins on hot catalystconveying from the XTO zone is a kind of catalyst cooler for the XTOreaction zone.

Although, it is better to perform the conversion of X-containingcompound and of the C4-C7 olefins in separate reaction zones likedescribed above in the XTO and OC reaction zone respectively, theolefins cracking being endothermic can be done by combining at least apart of the X-containing compound with the C4-C7 olefins in the OCreaction zone. The amount of X-containing compound converted shouldreduce the temperature loss due to the endothermic C4-C7 olefinscracking. The amount should advantageously not exceed the value when thecombined conversion becomes exothermic.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a process to make light olefins andaromatics, in a combined XTO-OC process, from an oxygen-containing,halogenide-containing or sulphur-containing organic feedstockcomprising:

a0) providing a first portion and a second portion of saidoxygen-containing, halogenide-containing or sulphur-containing organicfeedstock,a) providing a catalyst comprising zeolitic molecular sieves containingat least 10 membered ring pore openings or larger in their microporousstructure,b) providing an XTO reaction zone, an OC reaction zone and a catalystregeneration zone, said catalyst circulating in the three zones, suchthat at least a portion of the regenerated catalyst is passed to the OCreaction zone, at least a portion of the catalyst in the OC reactionzone is passed to the XTO reaction zone and at least a portion of thecatalyst in the XTO reaction zone is passed to the regeneration zone;c) contacting the first portion of said oxygen-containing,halogenide-containing or sulphur-containing organic feedstock in the XTOreactor with the catalyst at conditions effective to convert at least aportion of the feedstock to form a XTO reactor effluent comprising lightolefins and a heavy hydrocarbon fraction;d) separating said light olefins from said heavy hydrocarbon fraction;e) contacting said heavy hydrocarbon fraction and the second portion ofsaid oxygen-containing, halogenide-containing or sulphur-containingorganic feedstock in the OC reactor with the catalyst at conditionseffective to convert at least a portion of said heavy hydrocarbonfraction and oxygen-containing, halogenide-containing orsulphur-containing organic feedstock to light olefins and aromatics.

In a specific embodiment the amount of the second portion of “X” in theOC feed is such as the OC reactor works around the limit of exothermicand endothermic conditions. By way of example the proportion of saidsecond portion of “X” in the OC feed is about 15 to about 30% by weightand advantageously about 20 to 30%.

In another specific embodiment the second portion is 0, there is only afirst portion.

In another specific embodiment the second portion is up to 60 or 70 w %of the “X” feedstock.

the XTO reaction zone can be made of one or more reactors.the OC reaction zone can be made of one or more reactors.the regeneration zone can be made of one or more reactors.the XTO reaction zone and the OC reaction zone can be located in thesame reactor.The catalyst can be a mixture of two or more catalysts and optionally abinder. It is an essential feature of the present invention that thesame catalyst is used in the XTO and OC reaction zone.

It is desirable to have a substantially 100% conversion of the organiccompound in the XTO reactor. This conversion rate is adjusted byoptimization of contact time, reaction temperature and the frequency ofregeneration of the catalyst.

Advantageously the catalyst coming from the OC zone and flowing to theXTO section has to contain at least 0.1% carbon.

With regards to said effluent of the XTO process, “light olefins” meansethylene and propylene and the “heavy hydrocarbon fraction” is definedherein as the fraction containing hydrocarbons having a molecular weightgreater than propane, which means hydrocarbons having 4 carbon atoms ormore and written as C₄ ⁺. The C₄ ⁺ fraction can also contain co-boilingX-containing compounds, like methanol and other oxygenates.

According to an embodiment the catalyst is a P-modified zeolite. Thesephosphorus modified molecular sieves of the present invention areprepared based on MFI, MOR, MEL, clinoptilolite or FER crystallinealuminosilicate molecular sieves having an initial Si/Al ratioadvantageously between 4 and 500. These P-modified zeolites can also beobtained based on cheap crystalline alumosilicates with low Si/Al ratio(below 30). This provides a lower final catalyst cost.

The catalyst made of a P-modified zeolite can be the P-modified zeoliteitself or it can be the P-modified zeolite formulated into a catalyst bycombining with other materials that provide additional hardness orcatalytic activity to the finished catalyst product.

According to a first embodiment said P-modified zeolite is made by aprocess comprising in that order:

-   -   selecting a zeolite (advantageously with Si/Al ratio between 4        and 500) among H⁺ or NH₄ ⁺-form of MFI, MEL, FER, MOR,        clinoptilolite;    -   introducing P at conditions effective to introduce        advantageously at least 0.05 wt % of P;    -   separation of the solid from the liquid if any;    -   an optional washing step or an optional drying step or an        optional drying step followed by a washing step;    -   a calcination step.

Optionally the process to make said P-modified zeolite comprises thesteps of steaming and leaching. The method consists in steaming followedby leaching. It is generally known by the persons in the art that steamtreatment of zeolites, results in aluminium that leaves the zeoliteframework and resides as aluminiumoxides in and outside the pores of thezeolite. This transformation is known as dealumination of zeolites andthis term will be used throughout the text. The treatment of the steamedzeolite with an acid solution results in dissolution of theextra-framework aluminiumoxides. This transformation is known asleaching and this term will be used throughout the text. Then thezeolite is separated, advantageously by filtration, and optionallywashed. A drying step can be envisaged between filtering and washingsteps. The solution after the washing can be either separated, by way ofexample, by filtering from the solid or evaporated. P can be introducedby any means or, by way of example, according to the recipe described inU.S. Pat. No. 3,911,041, U.S. Pat. No. 5,573,990 and U.S. Pat. No.6,797,851. The separation of the liquid from the solid is advantageouslymade by filtering at a temperature between 0-90° C., centrifugation at atemperature between 0-90° C., evaporation or equivalent. Optionally, thezeolite can be dried after separation before washing. Advantageouslysaid drying is made at a temperature between 40-600° C., advantageouslyfor 1-10h. This drying can be processed either in static conditions orin a gas flow. Air, nitrogen or any inert gases can be used. The washingstep can be performed either during the filtering (separation step) witha portion of cold (<40° C.) or hot water (>40 but <90° C.) or the solidcan be subjected to a water solution (1 kg of solid/4 liters watersolution) and treated under reflux conditions for 0.5-10 h followed byevaporation or filtering. Final calcination step is performedadvantageously at the temperature 400-700° C. either in staticconditions or in a gas flow. Air, nitrogen or any inert gases can beused.

The catalyst made of a P-modified zeolite can be the P-modified zeoliteitself or it can be the P-modified zeolite formulated into a catalyst bycombining with other materials that provide additional hardness orcatalytic activity to the finished catalyst product.

According to an embodiment of the invention the phosphorous modifiedzeolite is made by a process comprising in that order:

-   -   selecting a zeolite (advantageously with Si/Al ratio between 4        and 500, from 4 to 30 in a specific embodiment) among H⁺ or NH₄        ⁺-form of MFI, MEL, FER, MOR, clinoptilolite;    -   steaming at a temperature ranging from 400 to 870° C. for        0.01-200h;    -   leaching with an aqueous acid solution at conditions effective        to remove a substantial part of Al from the zeolite;    -   introducing P with an aqueous solution containing the source of        P at conditions effective to introduce advantageously at least        0.05 wt % of P;    -   separation of the solid from the liquid;    -   an optional washing step or an optional drying step or an        optional drying step followed by a washing step;    -   a calcination step.

Optionally between the steaming step and the leaching step there is anintermediate step such as, by way of example, contact with silica powderand drying.

According to a second embodiment the catalyst of the combined XTO-OCprocess is a catalyst composite made by a process comprising thefollowing steps:

-   -   a). selecting a molecular sieve having pores of 10- or        more-membered rings    -   b). contacting the molecular sieve with a metal silicate        comprising at least one alkaline earth metal, such that the        composite comprises at least 0.1 wt % of silicate.

The molecular sieve is preferably brought into contact with the metalsilicate by one of the following two methods:

-   -   During the formulation step of the catalyst by mechanically        blending the molecular sieve with the metal silicate forming a        precursor to be used in the formulation step;    -   Physical blending of the previously formulated molecular sieve        and the previously formulated metal silicate in situ in the XTO        and/or OC reaction medium.

The molecular sieve could be selected from the list of MFI, MOR, MEL,clinoptilolite, FER, FAU, MWW, BETA, ZSM-21, ZSM-22, ZSM-23, ZSM-42,ZSM-57, LTL, or a mixture of thereof. Preferably, the MFI is a ZSM-5zeolite. More preferably, the molecular sieve is selected from the groupof MFI, MOR, MEL, clinoptilolite, FER or a mixture thereof. In anotherembodiment, the molecular sieve is preferably obtained without directaddition of template.

Said molecular sieve and/or said catalyst composite containing themolecular sieve and the metal silicate can be post-treated bycalcinations, reductions or steaming. In the case of using zeolites asmolecular sieve components, phosphorus can be introduced before,simultaneously or after blending with the metal silicate.

The composition of the catalyst composite comprises:at least 10 wt % of a molecular sieve having pores of 10- ormore-membered ringsat least one metal silicate comprising at least one alkaline earthmetal, such that the catalyst composite comprises at least 0.1 wt % ofsilicateoptionally metal phosphatesoptionally matrix materialoptionally a binder.

According to a third embodiment, the catalyst of the combined XTO-OCprocess is an alkaline earth or rare earth metal —P-modified molecularsieve (M-P-modified molecular sieve) made by a process comprising thefollowing steps:

a). selecting at least one molecular sieve selected from one of:

-   -   a P-modified molecular sieve which contains at least 0.3 wt % of        P    -   a molecular sieve which is modified with P prior to or during        step b) introducing at least 0.3 wt % of P    -   b). contacting said molecular sieve with an alkaline earth or        rare earth metal-containing compound (M-containing compound) to        introduce at least 0.05 wt % of the alkaline earth or rare earth        metal M.

Optionally, the contact of the molecular sieve with the P-containingcompound and the M-containing compound can be performed simultaneously.

The introduction of the alkaline earth or rare earth metal (M) isperformed by bringing the molecular sieve in contact with a solution ofone or more M-containing compounds. Said solution can contain a higherconcentration of the alkaline earth or rare earth metal than that foundin the final M-P-modified molecular sieve.

The modification of molecular sieves with phosphorous is known per se.This modification is carried out by treating molecular sieves withP-compounds in aqueous or non-aqueous media, by chemical vapordeposition of organic P-compounds or impregnation. The catalyst can bepre-formulated with binder or not. The preferred P-compounds usedtypically for this purpose can be selected from the group of phosphoricacid, NH₄H₂PO₄ or (NH₄)₂HPO₄.

The M-containing compound can be selected from organic compounds, salts,hydroxides and oxides. These compounds may also contain phosphorus. Itis essential that these compounds are present in solubilized form,before bringing them into contact with the molecular sieve or by forminga solution when in contact with the molecular sieve.

The final molar ratio M/P in the M-P-molecular sieve is preferably lessthan 1.

The molecular sieve can be selected from the list of MFI, MOR, MEL,clinoptilolite, FER, FAU, MWW, BETA, MCM-41, ZSM-21, ZSM-22, ZSM-23,ZSM-42, ZSM-57, LTL or a mixture thereof. More preferably, the molecularsieve is selected from the group of MFI, MOR, MEL, clinoptilolite, FERor a mixture thereof. In the case of MFI, the molecular sieve ispreferably a ZSM-5 zeolite. In another embodiment, the molecular sieveis preferably obtained without direct addition of template.

Preferably, the average pore size of the molecular sieve is at least 0.5nm. Said molecular sieve before modification with M and P, can becalcined, steamed, ion-exchanged, treated with acid solution or it mayundergo other treatments leading to dealumination. Dealumination of themolecular sieve can be performed simultaneously with the phosphorousmodification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a general flow of catalyst between OC reaction zone,XTO reaction zone and regeneration zone.

FIG. 2 illustrates an embodiment of separation section.

FIG. 3 illustrates flow of catalyst from regeneration zone to OCreaction zone, then to XTO reaction zone and finally to regenerationzone again.

FIG. 4 illustrates flow of catalyst from regeneration zone to OCreaction zone, then to XTO reaction zone and finally to regenerationzone again.

FIG. 5 illustrates an embodiment including a commondisengagement/cyclone zone for products and catalyst for XTO and OCzones.

FIG. 6 illustrates an embodiment including common disengagement/cyclonezone for products and catalyst for XTO and OC zones.

DETAILED DESCRIPTION OF THE INVENTION

As regards the first embodiment of the invention, and the selectedzeolite, advantageously it is a crystalline alumosilicate of the MFIfamily or the MEL family. An example of MFI silicates is ZSM-5. Anexample of an MEL zeolite is ZSM-11 which is known in the art. Otherexamples are described by the International Zeolite Association (Atlasof Zeolite Structure Types, 1987, Butterworths).

Crystalline silicates are microporous crystalline inorganic polymersbased on a framework of XO₄ tetrahydra linked to each other by sharingof oxygen ions, where X may be trivalent (e.g. Al, B, . . . ) ortetravalent (e.g. Ge, Si, . . . ). The crystal structure of acrystalline silicate is defined by the specific order in which a networkof tetrahedral units are linked together. The size of the crystallinesilicate pore openings is determined by the number of tetrahedral units,or, alternatively, oxygen atoms, required to form the pores and thenature of the cations that are present in the pores. They possess aunique combination of the following properties: high internal surfacearea; uniform pores with one or more discrete sizes; ionexchangeability; good thermal stability; and ability to adsorb organiccompounds. Since the pores of these crystalline alumosilicates aresimilar in size to many organic molecules of practical interest, theycontrol the ingress and egress of reactants and products, resulting inparticular selectivity in catalytic reactions. Crystallinealumosilicates with the MFI structure possess a bi-directionalintersecting pore system with the following pore diameters: a straightchannel along [010]: 0.53-0.56 nm and a sinusoidal channel along [100]:0.51-0.55 nm. Crystalline alumosilicates with the MEL structure possessa bi-directional intersecting straight pore system with straightchannels along [100] having pore diameters of 0.53-0.54 nm.

Advantageously the selected MFI, MEL, FER, MOR, clinoptilolite (or H⁺ orNH₄ ⁺-form MFI, MEL, FER, MOR, clinoptilolite) has an initial atomicratio Si/Al of 100 or lower and from 4 to 30 in a specific embodiment.The conversion to the H⁺ or NH₄ ⁺-form is known per se and is describedin U.S. Pat. No. 3,911,041 and U.S. Pat. No. 5,573,990.

In the steam treatment step, the temperature is preferably from 420 to870° C., more preferably from 480 to 760° C. The pressure is preferablyatmospheric pressure and the water partial pressure may range from 13 to100 kPa. The steam atmosphere preferably contains from 5 to 100 vol %steam with from 0 to 95 vol % of an inert gas, preferably nitrogen. Thesteam treatment is preferably carried out for a period of from 0.01 to200 hours, advantageously from 0.05 to 200 hours, more preferably from0.05 to 50 hours. The steam treatment tends to reduce the amount oftetrahedral aluminium in the crystalline silicate framework by formingalumina.

The leaching can be made with an organic acid such as citric acid,formic acid, oxalic acid, tartaric acid, malonic acid, succinic acid,glutaric acid, adipic acid, maleic acid, phthalic acid, isophthalicacid, fumaric acid, nitrilotriacetic acid,hydroxyethylenediaminetriacetic acid, ethylenediaminetetracetic acid,trichloroacetic acid trifluoroacetic acid or a salt of such an acid(e.g. the sodium salt) or a mixture of two or more of such acids orsalts. The other inorganic acids may comprise an inorganic acid such asnitric acid, hydrochloric acid, methansulfuric acid, phosphoric acid,phosphonic acid, sulfuric acid or a salt of such an acid (e.g. thesodium or ammonium salts) or a mixture of two or more of such acids orsalts.

Advantageously the final P-content is at least 0.05 wt % and preferablybetween 0.3 and 7 w %. Advantageously at least 10% of Al, in respect toparent zeolite MFI, MEL, FER, MOR and clinoptilolite, have beenextracted and removed from the zeolite by the leaching.

Then the zeolite either is separated from the washing solution or isdried without separation from the washing solution. Said separation isadvantageously made by filtration. Then the zeolite is calcined, by wayof example, at 400° C. for 2-10 hours.

The residual P-content is adjusted by P-concentration in the aqueousacid solution containing the source of P, drying conditions and awashing procedure if any. A drying step can be envisaged betweenfiltering and washing steps.

The P-modified zeoilite can be used as itself as a catalyst. In anotherembodiment it can be formulated into a catalyst by combining with othermaterials that provide additional hardness or catalytic activity to thefinished catalyst product. Materials which can be blended with theP-modified zeolite can be various inert or catalytically activematerials, or various binder materials. These materials includecompositions such as kaolin and other clays, various forms of rare earthmetals, phosphates, alumina or alumina sol, titania, zirconia, quartz,silica or silica sol, and mixtures thereof. These components areeffective in densifying the catalyst and increasing the strength of theformulated catalyst. The catalyst may be formulated into spray-driedparticles. The amount of P modified zeoilite which is contained in thefinal catalyst product ranges from 10 to 90 weight percent of the totalcatalyst, preferably 20 to 70 weight percent of the total catalyst.

As regards the second embodiment of the invention, The molecular sievesthat can be used in the invention are preferably zeolites, for examplecrystalline silicates, more precisely aluminosilicates. Crystallinesilicates are microporous crystalline inorganic polymers based on aframework of XO₄ tetrahydra linked to each other by sharing oxygen ions,where X may be trivalent (e.g. Al, B, Ga. . . ) or tetravalent (e.g. Ge,Si, . . . ). The crystal structure of a crystalline silicate is definedby the specific order in which a network of tetrahedral units are linkedtogether. The size of the crystalline silicate pore openings isdetermined by the number of tetrahedral units, or, alternatively, oxygenatoms, required to form the pores and the nature of the cations that arepresent in the pores. They possess a unique combination of the followingproperties: high surface area; uniform pores with one or more discretesizes; ion exchangeability; good thermal stability; and ability toadsorb organic compounds. Since the pores of these crystallinealuminosilicates are similar in size to many organic molecules ofpractical interest, they control the ingress and egress of reactants andproducts, resulting in particular selectivity in catalytic reactions.

The selected molecular sieve can be made with the help of the seedingtechnique, but advantageously they are made without template. However,the seeds themselves may have been made with a template, which means inthis case that the molecular sieve is made without direct addition of atemplate. It is preferred that the molecular sieve used in the inventionis made without direct addition of template.

The molecular sieves selected for the purposes of this invention havepores of the size of 10 or more-membered rings. It can be envisaged touse molecular sieves, which have ring pores consisting of 10, 12 or moremembers. The selected molecular sieve according to the present inventionhas an average pore size of at least 0.5, preferably from 0.5 to 10,more preferably from 0.5 to 5 and most preferably at least from 0.5 to0.9 nm.

The selected molecular sieve has an initial atomic ratio Si/Al of atleast 4 and not greater than 500. The Si/Al atomic ratio is measured bychemical analysis, for example using XRF and/or NMR. It includes onlythose Al that are part of the framework structure of the molecularsieve.

As regards to the selected molecular sieve, advantageously it isselected from the group of MFI, MOR, MEL, clinoptilolite, FER, FAU, MWW,BETA, ZSM-21, ZSM-22, ZSM-23, ZSM-42, ZSM-57, LTL, or mixtures thereof,according to the International Zeolite Association (Atlas of ZeoliteStructure Types, 1987, Butterworths). Preferably it is selected fromgroup of the MFI, MOR, MEL, clinoptilolite, FER or a mixture of thereof.More preferably, the MFI is a ZSM-5 zeolite.

In another embodiment, the molecular sieve selected from the group ofMFI, MOR, MEL, clinoptilolite, FER or a mixture of, is preferablyobtained without direct addition of template.

The molecular sieve may be used as synthesised to form the catalystcomposite. Prior to formulation of the catalyst composite the molecularsieve may undergo further treatments including steaming, leaching (e.g.acid leaching), washing, drying, calcination, impregnation and ionexchanging steps. In addition or alternatively, these steps can also becarried out after formulation of the catalyst composite.

In a particular embodiment of the invention, the molecular sieve can bemodified either prior to or after introduction of the metal silicate.Preferably, the molecular sieve has undergone some form of modificationprior to the metal silicate introduction. By modification, it is meantherein that the molecular sieve may have undergone steaming, leaching(e.g. acid leaching), washing, drying, calcination, impregnation or someform of ion-exchange. This means that at least a portion of the cationsoriginally comprised in the crystal structure can be replaced with awide variety of other cations according to techniques well known in theart. The replacing cations can be hydrogen, ammonium or other metalcations, including mixtures of such cations.

The selected molecular sieve is then formulated into a catalystcomposite to comprise at least 10% by weight of a molecular sieve asdescribed herein and at least one metal silicate comprising at least onealkaline earth metal, such that the composite comprises at least 0.1% byweight of silicate.

At least one of the metal silicates comprised in the catalyst compositeincludes at least one alkaline earth metal, preferably Ca. Metalsilicates are insoluble in water and alkaline earth metal ions,particularly calcium, are polyvalent and possess a large radius in thehydrated state. Thus, without wishing to be bound by theory, it isthought that the ion exchange reaction with the molecular sieve occursvery slowly, as the alkaline earth metal ion must lose many of itsstrongly coordinated water molecules in order to penetrate into themicropores of the molecular sieve structure. As a result, the alkalineearth metal ions expose only the acid sites located on the externalsurface of the molecular sieve, and thus increasing the selectivity ofthe catalyst.

Furthermore, without wishing to be bound by theory, it is thought thatthe presence of silicate anions further improve the catalytic propertiesof the catalyst composite. The silicate anions, for example, can supplysilicon atoms to heal defects in the molecular sieve. This can thus leadto additional stabilisation of the catalyst under severe hydrothermalconditions.

As a result the metal silicate acts as a catalyst promoter.

The metal silicate can comprise more than one alkaline earth metalselected from Ca, Mg, Sr and Ba.

The metal silicates may also comprise other metals selected from one ormore of the following: Ga, Al, Ce, In, Cs, Sc, Sn, Li, Zn, Co, Mo, Mn,Ni, Fe, Cu, Cr, Ti and V. Preferably, the other metal is selected fromone or more of Al, Mg, Ce, Co and Zn or mixtures thereof. These bi-,tri- or polymetal silicates can be synthesised according to any methodknown in the art. This can be for example by ion exchange in thesolution or solid state (Labhsetwar et al., Reactivity of Solids, Vol.7, Issue 3, 1989, 225-233).

The silicate anion can be present in any form in the solid metalsilicate. Examples include SiO3²⁻, SiO4⁴⁻, Si₂O₇ ⁶⁻, Si₃O₁₀ ⁸⁻ and thelike.

The preferred catalyst promoter is a calcium silicate with a very openand accessible pore structure. An even more preferred catalyst promotercomprises a synthetic crystalline hydrated calcium silicate having achemical composition of Ca₆Si₆O₁₇(OH)₂ which corresponds to the knownmineral xonotlite (having a molecular formula 6CaO.6SiO₂.H₂O).

Generally, a synthetic hydrated calcium silicate is synthesisedhydrothermally under autogeneous pressure. A particularly preferredsynthetic hydrated calcium silicate is available in commerce from thecompany Promat of Ratingen in Germany under the trade name Promaxon.

In order to demonstrate the thermal stability of xonotlite, andtherefore the applicability of xonotlite as a catalyst promoter in MTOand OC, commercial xonotlite sold under the trade name Promaxon D wascalcined in ambient air at a relative humidity of about 50% at 650° C.for a period of 24 hours. The initial xonotlite had a crystalline phaseCa₆Si₆O₁₇(OH)₂ with a BET surface area of 51 m²/gram and a pore volume(of less than 100 nanometres) of 0.35 ml/gram. After calcination at 650°C., the carrier retained its crystallinity, which corresponds to that ofxonotlite. Thus after a 24 hour calcination at 650° C., the crystallinephase still comprised xonotlite (Ca₆Si₆O₁₇(OH)₂) with a BET surface areaof 47.4 m²/gram and a pore volume (less than 100 nanometres) of 0.30ml/gram.

Other examples of metal silicates comprising alkaline earth metalsinclude CaAl₂Si₂O₈, Ca₂Al₂SiO₇, CaMg(Si₂O₆)_(x), as well as mixturesthereof.

Before mixing with the molecular sieve said metal silicate compounds maybe modified by calcination, steaming, ion-exchange, impregnation, orphosphatation. Said metal silicates may be an individual compound or maybe a part of mixed compounds.

The metal silicate can be brought into contact with the molecular sieveby a simultaneous formulation step of a blend of the metal silicate withthe molecular sieve or in situ blending of separately formulatedmaterials in the reaction medium prior to the XTO or OC process. Saidcontact can be realised by mechanically blending of the molecular sievewith the alkaline earth metal-comprising metal silicate. This can becarried out via any known blending method. Blending can last for aperiod of time starting from 1 minute up to 24 hours, preferably from 1min to 10 hours. If not carried out in the XTO or OC reactor in situ, itcan be carried out in a batchwise mixer or in a continuous process, suchas in an extruder e.g. a single or twin screw extruder at a temperatureof from 20 to 300° C. under vacuum or elevated pressure. Said contactmay be performed in an aqueous or non-aqueous medium. Prior to theformulation step, other compounds that aid the formulation may be added,like thickening agents or polyelectrolytes that improve the cohesion,dispersion and flow properties of the precursor. In case of oil-drop orspray-drying a rather liquid (high water content) is prepared. Inanother embodiment, the contact is carried out in the presence ofphosphorus containing compounds. In a particular embodiment, the contactis carried out in the aqueous medium at pH lower than 5, more preferablylower than 3.

Either prior to, after or simultaneously with the formulation step toform the composite, other components may be optionally blended with themolecular sieve. In a particular embodiment, the molecular sieve can becombined with other materials that provide additional hardness orcatalytic activity to the finished catalyst product. Materials, whichcan be blended with the molecular sieve, can be various inert orcatalytically active matrix materials and/or various binder materials.Such materials include clays, silica and/or metal oxides such asalumina. The latter is either naturally occurring or in the form ofgelatinous precipitates or gels including mixtures of silica and metaloxides. In an embodiment, some binder materials can also serve asdiluents in order to control the rate of conversion from feed toproducts and consequently improve selectivity. According to oneembodiment, the binders also improve the attrition of the catalyst underindustrial operating conditions.

Naturally occurring clays, which can be used as binder, are for exampleclays from the kaolin family or montmorillonite family. Such clays canbe used in the raw state as mined or they can be subjected to varioustreatments before use, such as calcination, acid treatment or chemicalmodification.

In addition to the foregoing, other materials which can be included inthe catalyst composite of the invention include various forms of metals,phosphates (for instance metal phosphates, wherein the metal is chosenfrom one or more of Ca, Ga, Al, Ca, Ce, In, Cs, Sr, Mg, Ba, Sc, Sn, Li,Zn, Co, Mo, Mn, Ni, Fe, Cu, Cr, Ti and V), alumina or alumina sol,titania, zirconia, quartz, silica or silica sol, and mixtures thereof.Examples of possible phospates include amorphous calcium phosphatemonocalcium phosphate, dicalcium phosphate, dicalcium phosphatedehydrate, α- or β-tricalcium phosphate, octacalcium phosphate,hydroxyapatite etc.

Examples of possibly binary oxide binder compositions include,silica-alumina, silica magnesia, silica-zirconia, silica-thoria,silica-beryllia, silica-titania, calcium-alumina. Examples of ternarybinder compositions include for instance calcium-silica-alumina orsilica-alumina-zirconia.

These components are effective in increasing the density of the catalystand increasing the strength of the formulated catalyst. The catalystusable in fluidised bed reactors has substantially spherical shape,formed typically by spray-drying. Generally, the size of the catalystparticles can vary from about 20 to 500 μm, more preferable from 30 to100 μm The crystal size of the molecular sieve contained in the catalystcomposite, is preferably less than about 10 μm, more preferably lessthan about 5 μm and most preferably less than about 2 μm. The amount ofmolecular sieve, which is contained in the final catalyst compositeranges from 10 to 90% by weight of the total catalyst composite,preferably 20 to 70% by weight.

According to another embodiment, non-modified molecular sieves werefirst formulated with a binder and matrix materials and then modifiedwith phosphorous and alkaline earth metal silicates.

According to a further particular embodiment, molecular sieves wereoptionally dealuminated and then modified with phosphorous during theformulation step. Introduction of the alkaline earth metal silicate canbe performed during the formulation step or on the formulated solid.

According to a preferred embodiment, molecular sieves were firstoptionally dealuminated and modified with phosphorous and thenformulated. Introduction of the metal is performed simultaneously withthe phosphorous modification step and/or on the already formulatedcatalyst.

After formulation, the catalyst composite may undergo further treatmentsincluding further steaming, leaching, washing, drying, calcination,impregnations and ion exchanging steps. If the molecular sieve was notmodified with phosphorus prior to the formulation step of the blend i.e.the step introducing the metal silicate to the molecular sieve, it maybe carried out after such a step.

According to a specific feature of this second embodiment, the molecularsieve is a phosphorus-modified (P-modified) zeolite. Saidphosphorus-modified (P-modified) zeolite has already described above.

As regards the third embodiment of the invention, the molecular sieveshave already been described in the second embodiment. Prior toP-modification and/or to the alkaline earth or rare earthmetal-modification (M-modification), the molecular sieve may undergofurther treatments including steaming, leaching (e.g. acid leaching),washing, drying, calcination, impregnation and ion exchanging steps. Inaddition or alternatively, these steps can also be carried out during orafter P-modification. By ion exchanging steps, it is meant herein thatat least a portion of the cations originally comprised in the crystalstructure are replaced with a wide variety of other cations according totechniques well known in the art. The replacing cations can be hydrogen,ammonium or other metal cations, including mixtures of such cations.

For the purposes of this invention, modification of the molecular sievewith P must be carried out prior to or during M-modification, if theselected molecular sieve is not already P-modified. Preferably, theP-modification is carried out via a dealuminating steaming step followedby a leaching step using any acidic solution containing a source of P,preferably a solution of phosphoric acid. Preferably, the P-modifiedmolecular sieve comprises at least 0.3% of phosphorus by weight of themolecular sieve.

According to one embodiment of the invention, the molecular sieve can bemodified with phosphorus according to the process comprising thefollowing steps, in the order given:

-   -   steaming of the molecular sieve at a temperature ranging from        400 to 870° C. for 0.01-200h;    -   leaching with an aqueous acid solution containing the source of        P at conditions effective to remove a substantial part of Al        from the molecular sieve and to introduce at least 0.3% of        phosphorus by weight of the molecular sieve;

Further modification can then be carried out according to the followingsteps, in the order given:

-   -   separation of the solid from the liquid;    -   an optional washing step or an optional drying step or an        optional drying step followed by a washing step;    -   a calcination step.

Preferably, separation, optional washing and drying steps andcalcination are carried out after introduction of the M-containingcompound to the molecular sieve. The metal M can be any alkaline earthor rare earth metal. Preferably the alkaline earth metal is Ca. However,it is also possible to use Mg, Sr and Ba. Possible rare earth metalsinclude La and Ce.

In the steam treatment step, the temperature is preferably from 420 to870° C., more preferably from 480 to 760° C. The pressure is preferablyatmospheric pressure and the water partial pressure may range from 13 to100 kPa. The steam atmosphere preferably contains from 5 to 100 vol %steam with from 0 to 95 vol % of an inert gas, preferably nitrogen. Thesteam treatment is preferably carried out for a period of from 0.05 to200 hours, more preferably from 0.05 to 50 hours. It is generally knownby the persons in the art that steam treatment of molecular sievesresults in aluminium that leaves the molecular sieve framework andresides as aluminiumoxides in and outside the pores of the molecularsieve. This transformation is known as dealumination of molecular sievesand this term will be used throughout the text.

The treatment of the steamed molecular sieve with an acid solutionresults in dissolution of the extra-framework aluminiumoxide. Thistransformation is known as leaching and this term will be usedthroughout the text. The leaching with an aqueous acid solutioncontaining the source of phosphorus is advantageously made under refluxconditions, meaning boiling temperature of the solution.

Amount of said acid solution is advantageously between 2 and 10 litresper kg of molecular sieve. A typical leaching period is around 0.5 to 24hours. Advantageously the aqueous acid solution containing the source ofP in the leaching step has a pH of 3, advantageously 2, or lower.Advantageously said aqueous acid solution is a solution of phosphorusacids, a mixture of phosphorus acids and organic or inorganic acids ormixtures of salts of phosphorus acids and organic or inorganic acids.The phosphorus acids or the corresponding salts can be of the phosphate([PO₄]³⁻, being tribasic), phosphite ([HPO₃]²⁻, being dibasic), orhypophosphite ([H₂PO₂]¹⁻, being monobasic), type. Of the phosphate typealso di- or polyphosphates ([P_(n)O_(3n+1)]^((n+2)−)) can be used. Theother organic acids may comprise an organic acid such as citric acid,formic acid, oxalic acid, tartaric acid, malonic acid, succinic acid,glutaric acid, adipic acid, maleic acid, phthalic acid, isophthalicacid, fumaric acid, nitrilotriacetic acid,hydroxyethylenediaminetriacetic acid, ethylenediaminetetracetic acid,trichloroacetic acid trifluoroacetic acid or a salt of such an acid(e.g. the sodium salt) or a mixture of two or more of such acids orsalts. The other inorganic acids may comprise an inorganic acid such asnitric acid, hydrochloric acid, methansulfuric acid, sulfuric acid or asalt of such an acid (e.g. the sodium or ammonium salts) or a mixture oftwo or more of such acids or salts.

It has been found that phosphorus acid is very efficient in complexingthe extra-framework aluminiumoxides and hence removing them from themolecular sieve solid material. Unexpectedly, a larger quantity ofphosphorus than what could be expected from the typical pore volume ofthe molecular sieve and assuming that the pores of the molecular sievesare filled with the used phosphorus acid solution, stays in the solidmolecular sieve material. Both factors i.e. dealumination and theretention of P, stabilise the lattice aluminium in the zeolitic lattice,thus avoiding further dealumination. This leads to a higher hydrothermalstability, tuning of the molecular sieve's properties and adjustment ofacid properties, thereby increasing the molecular sieve's selectivity.The degree of dealumination can be adjusted by the steaming and leachingconditions.

Advantageously, the final P-content of the molecular sieve is at least0.3 wt % and preferably between 0.3 and 7 w %. Advantageously at least10% of Al have been extracted and removed from the molecular sieve bythe leaching. The residual P-content is adjusted by the P-concentrationin the leaching solution, separating conditions during the separation ofthe solid from the liquid and/or the optional washing procedure duringwhich impregnation and/or adsorption can also take place. A drying stepcan be envisaged between the separation and/or washing steps.

The molecular sieve is then either separated from the washing solutionor is dried without separation from the washing solution. Saidseparation is advantageously made by filtration. Then the molecularsieve is calcined, by way of example, at 400° C. for 2-10 hours.

M-modification of the molecular sieve is carried out either on analready P-modified molecular sieve or during/after the P-modificationprocess. P-modification can be carried out as described above whereinthe sieve is dealuminated by steaming, then leached with a P-containingacid solution. In this case, advantageously, treatment of the molecularsieve with the M-containing solution is performed after the leaching orwashing step i.e. after the phosphorous compound has been added andP-modification has taken place and before the separation step. However,the introduction of M to the molecular sieve can also be envisaged:

-   -   during the leaching step,    -   before the washing step but after leaching and drying    -   on calcined molecular sieves that have been contacted with P    -   on molecular sieve that has not been leached to introduce P but        has been contacted with P during the washing step introduction        of M on the molecular sieves can be performed either by        impregnation or by adsorption from an aqueous solution of        M-containing compounds.

The introduction of the M-containing compound can be done attemperatures ranging from ambient temperature up to the boiling point ofthe solution.

The concentration of the M-containing compound in the solution is atleast 0.05-M, preferably between 0.05 and 1.0 M. The amount of thealkaline earth or rare earth metal (M) in the M-P-molecular sieves canvary from at least 0.05% by weight, preferably 0.05 to 7% by weight,most preferably from 0.1 to 4% by weight.

Prior to formulation of the catalyst composite the molecular sieve mayundergo further treatments including steaming, leaching (e.g. acidleaching), washing, drying, calcination, impregnation and ion exchangingsteps. In addition or alternatively, these steps can also be carried outafter formulation of the catalyst composite.

The alkaline earth or rare earth metal M is preferably selected from oneor more of: Mg, Ca, Sr, Ba, La, Ce. More preferably, M is an alkalineearth metal. Most preferably, M is Ca. Particularly in the case ofP-modification via steaming and leaching, M can be a rare earth metalsuch as La and Ce.

The M-containing compound is preferably in the form of an organiccompound, a salt, hydroxide or oxide. The compound is preferably in asolubilized form when bringing it into contact with the molecular sieve.Alternatively, the solution of the M-containing compound can be formedafter bringing the molecular sieve in contact with said compound.

Possible M-containing compounds include metal M compounds such as metalM sulphate, formate, nitrate, acetate, halides, oxyhalides, borates,carbonate, hydroxide, oxide and mixtures thereof. These can be forexample, calcium sulphate, formate, nitrate, acetate, halides,oxyhalides, borates, carbonate, hydroxide, oxide and mixtures thereof.

The M-containing compound may also include other metals chosen from oneor more of Mg, Sr, Ba, Ga, Al, Ce, In, Cs, Sc, Sn, Li, Zn, Co, Mo, Mn,Ni, Fe, Cu, Cr, Ti and V. The M-containing compounds may alsoadditionally comprise phosphorus.

Those M-containing compounds, which are poorly water-soluble, can bedissolved to form a well-solubilized solution by heating and/or bymodifying the pH of the solution by addition of phosphoric, acetic ornitric acid or corresponding ammonium salts of said acids. Theconcentration of the M-containing compound is at least 0.05 M.

The alkaline earth and rare earth metals M, in particular Ca, possess alarge hydration sphere radius in the hydrated state. Thus, withoutwishing to be bound by theory, it is thought that the ion exchangereaction with the acid sites located on the inside of the microporestructures of the molecular sieve occurs very slowly. As a result, thechosen metal M exposes only the acid sites located on the externalsurface of the molecular sieve, and thus increasing the selectivity ofthe catalyst.

In the case of P-modified molecular sieves, M-modification leads to theformation of mixed M-Al-phosphates on the external surface. Taking intoaccount that phosphorous is bound with the alkaline earth or rare earthmetal M more strongly than with Al, this modification leads tostabilization of phosphorous on the external surface of the molecularsieve where the phosphorous is the most labile. However, it isessential, that all the M atoms located on the external surface aresaturated with phosphorous. This can be guaranteed in the presence of anexcess of phosphorous and by the presence of M in solution form, whichis, for example, used to wash the excess phosphorous away preventing aplugging of the entrance to micropores.

Formulation into a catalyst composite can be carried out once theM-P-modified molecular sieve has been obtained i.e. other components maybe optionally blended with the molecular sieve. (However, theM-P-modified molecular sieve can also be used as such as a catalyst.)

According to one embodiment, the prepared M-P-modified molecular sieveis co-formulated into a catalyst composite to comprise at least 10% byweight of the M-P-molecular sieve as described herein and at least 0.05%by weight of M and at least 0.3% by weight of phosphorous, both inrelation to the weight of the molecular sieve.

In a particular embodiment, the molecular sieve can be combined withother materials that provide additional hardness or catalytic activityto the finished catalyst product. Materials, which can be blended withthe molecular sieve, can be various inert or catalytically active matrixmaterials and/or various binder materials. Such materials include clays,silica and/or metal oxides such as alumina.

According to another embodiment, non-modified molecular sieve was firstformulated with a binder and a matrix materials and then modified withphosphorous and metals.

According to particular embodiment, molecular sieves were optionallydealuminated and then modified with phosphorous during formulation step.Introduction of the metal can be performed during the formulation stepor on the formulated solid.

According to preferred embodiment, molecular sieves was first optionallydealuminated and modified with phosphorous and then formulated.Introduction of the metal is performed simultaneously with modificationwith phosphorous step or/and on formulated catalyst.

The catalyst composite may also optionally comprise binder and/or matrixmaterial and/or metal phosphate. Preferably, the amount of molecularsieve, which is contained in the final catalyst composite can range from10 to 90% by weight of the total catalyst composite, more preferablyfrom 20 to 70% by weight. The concentration of M in the formulatedcatalyst can be higher than the M concentration in the molecular sievealone, because the binder or matrix material may also contain someM-compounds.

Naturally occurring clays, which can be used as binder, are for exampleclays from the kaolin family or montmorillonite family. Such clays canbe used in the raw state as mined or they can be subjected to varioustreatments before use, such as calcination, acid treatment or chemicalmodification.

In addition to the foregoing, other materials which can be included inthe catalyst composite of the invention include various forms of metals,phosphates (for instance metal phosphates, wherein the metal is chosenfrom one or more of Ca, Ga, Al, Ca, Ce, In, Cs, Sr, Mg, Ba, Sc, Sn, Li,Zn, Co, Mo, Mn, Ni, Fe, Cu, Cr, Ti and V), alumina or alumina sol,titania, zirconia, quartz, silica or silica sol, and mixtures thereof.Examples of possible phosphates include amorphous metal phosphates, andmetal phosphates such as calcium phosphates e.g. monocalcium phosphate,dicalcium phosphate, dicalcium phosphate dehydrate, α- or β-tricalciumphosphate, octacalcium phosphate, hydroxyapatite etc. Examples ofpossibly binary binder compositions include, silica-alumina, silicamagnesia, silica-zirconia, silica-thoria, silica-beryllia,silica-titania, calcium-alumina and calcium silicate. Examples ofternary binder compositions include for instance calcium-silica-aluminaor silica-alumina-zirconia.

With regards to the XTO reaction zone, in this process a feedstockcontaining an oxygen-containing, halogenide-containing orsulphur-containing organic compound contacts the above describedcatalyst in a reaction zone of a reactor at conditions effective toproduce light olefins, particularly ethylene and propylene. Typically,the oxygen-containing, halogenide-containing or sulphur-containingorganic feedstock is contacted with the catalyst when theoxygen-containing, halogenide-containing or sulphur-containing organiccompound is in vapour phase. Alternately, the process may be carried outin a liquid or a mixed vapour/liquid phase. In this process, convertingoxygen-containing, halogenide-containing or sulphur-containing organiccompounds, olefins can generally be produced at a wide range oftemperatures. An effective operating temperature range can be from about200° C. to 700° C. At the lower end of the temperature range, theformation of the desired olefin products may become markedly slow. Atthe upper end of the temperature range, the process may not form anoptimum amount of product. An operating temperature of at least 300° C.,and up to 600° C. is preferred.

The pressure also may vary over a wide range. Preferred pressures are inthe range of about 5 kPa to about 5 MPa, with the most preferred rangebeing of from about 50 kPa to about 0.5 MPa. The foregoing pressuresrefer to the partial pressure of the oxygen-containing,halogenide-containing, sulphur-containing organic compounds and/ormixtures thereof.

The process can be carried out in any system using a variety offluidized bed reactors. It is particularly desirable to operate thereaction process at high space velocities. The process can be conductedin a single reaction zone or a number of reaction zones arranged inseries or in parallel. After a certain time-on-stream the catalyst needsto be regenerated. This regeneration is carried out in the regenerationzone. The commercial scale reactor systems can be operated at a weighthourly space velocity (WHSV) of from 0.1 hr′ to 1000 hr′.

One or more inert diluents may be present in the feedstock of the XTOreaction zone, for example, in an amount of from 1 to 95 molar percent,based on the total number of moles of all feed and diluent componentsfed to the reaction zone. Typical diluents include, but are notnecessarily limited to helium, argon, nitrogen, carbon monoxide, carbondioxide, hydrogen, water, paraffins, alkanes (especially methane,ethane, and propane), aromatic compounds, and mixtures thereof. Thepreferred diluents are water and nitrogen. Water can be injected ineither liquid or vapour form.

The use of a diluents can provide two advantages. The first advantage isthat it reduces the partial pressure of the X and hence will improve theselectivity for light olefins, mainly propylene. The result is thatlower reaction temperatures can be used. Generally, the lower thepartial pressure of X, the higher the light olefin selectivity. Thereexist an optimum for light olefin yield depending on the partialpressure, reaction temperature and catalyst properties.

The second advantage of using a diluents is that it can acts as a heatsink for the exothermic X conversion. So the higher the specific molarheat capacity, the more heat can be absorbed by the diluents. Thissecond advantage might be less important in case of fluidised bedreactors as the latter are known to be excellent reactors to run at nearhomogeneous temperature throughout the catalyst bed. It is preferredthat the diluents can be easily separated from the light olefinsproducts, preferentially by simply phase separation. Hence a preferreddiluents is water. Diluents can be added from 1 to 95 mole percent ofthe combined feed (X+ diluents), preferably from 10 to 75 mole percent.

According to a specific embodiment essentially no water (or steam) isinjected as diluent of the feedstock sent to the XTO reactor. However itmeans that the feedstock can contain the water already contained in thefresh oxygen-containing, halogenide-containing or sulphur-containingorganic feedstock or the steam used to engage the proper flowing andpurging of catalyst in fluidised bed reactors of the XTO reactor.

The oxygenate feedstock is any feedstock containing a molecule or anychemical having at least an oxygen atom and capable, in the presence ofthe above catalyst, to be converted to olefin products. The oxygenatefeedstock comprises at least one organic compound which contains atleast one oxygen atom, such as aliphatic alcohols, ethers, carbonylcompounds (aldehydes, ketones, carboxylic acids, carbonates, esters andthe like). Representative oxygenates include but are not necessarilylimited to lower straight and branched chain aliphatic alcohols andtheir unsaturated counterparts. Examples of suitable oxygenate compoundsinclude, but are not limited to: methanol; ethanol; n-propanol;isopropanol; C₄-C₂₀ alcohols; methyl ethyl ether; dimethyl ether;diethyl ether; di-isopropyl ether; formaldehyde; dimethyl carbonate;dimethyl ketone; acetic acid; and mixtures thereof. Representativeoxygenates include lower straight chain or branched aliphatic alcohols,their unsaturated counterparts. Analogously to these oxygenates,compounds containing sulphur or halides may be used. Examples ofsuitable compounds include methyl mercaptan; dimethyl sulfide; ethylmercaptan; di-ethyl sulfide; ethyl monochloride; methyl monochloride,methyl dichloride, n-alkyl halides, n-alkyl sulfides having n-alkylgroups of comprising the range of from about 1 to about 10 carbon atoms;and mixtures thereof. Preferred oxygenate compounds are methanol,dimethyl ether, or a mixture thereof.

In XTO effluent among the olefins having 4 carbon atoms or more thereare more then 50 weight % of butenes.

With regards to said effluent of the XTO process, “light olefins” meansethylene and propylene and the “heavy hydrocarbon fraction” is definedherein as the fraction containing hydrocarbons having a molecular weightgreater than propane, which means hydrocarbons having 4 carbon atoms ormore and written as C₄ ⁺. The C₄ ⁺ fraction can also contain otherco-boiling X-containing compounds, like methanol and other oxygenates.

The heavy hydrocarbon fraction produced in the XTO reactor is convertedin the OC reactorto produce additional amounts of ethylene and propyleneand aromatics.

As regards the OC reaction zone, various reaction pathways can occur onthe catalyst. Under the process conditions, having an inlet temperatureof around 350° to 600° C., preferably from 380° to 580° C., yet morepreferably 400° to 560° C., and an olefin partial pressure of from 0.1to 10 bars, most preferably around 1 to 5 bars pressure.

In the catalytic cracking process of the OC reactor, the processconditions are selected in order to provide high selectivity towardspropylene or ethylene and aromatics, as desired, a stable olefinconversion over time. Such objectives are favoured with a mediumpressure, a medium inlet temperature and a reasonable high contact time,all of which process parameters are interrelated and provide an overallcumulative effect.

The process conditions are selected to favour hydrogen transferreactions leading to the formation of paraffins on one hand andaromatics on the other hand. The process operating conditions thusemploy a low space velocity, a medium pressure and a medium reactiontemperature. The LHSV ranges from 0.5 to 10 hr′, preferably from 1 to 5hr′. The olefin partial pressure ranges from 0.5 to 10 bars, preferablyfrom 1.0. to 5 bars (absolute pressures referred to herein). The heavyhydrocarbon fraction feedstock is preferably fed at a total inletpressure sufficient to convey the feedstocks through the reactor. Theconversion of the olefins is preferably performed at an inlettemperature of the feedstock of from 350° to 600° C., more preferablyfrom 380° to 580° C., yet more preferably from 400° C. to 560° C.

The conversion of heavy olefins is slightly endothermic and will hencereduce the temperature of the reaction products and catalyst compared tothe feedstock temperature. On the other hand the conversion ofX-containing compound is highly exothermic and will hence increase thetemperature of the reaction products and catalyst compared to thefeedstock temperature. So, it is preferred that a part of theX-containing feedstock is sent together with the heavy olefins to the OCreaction zone. It is a preferred embodiment that the temperature drop ofthe reaction products and catalyst compared to the feedstock temperatureapproaches zero. It is preferred that the temperature drop of thereaction products and catalyst at the reactor outlet compared to thefeedstock temperature at the inlet of the reactor is reduced with 10 to95% of the temperature drop expected when no X-containing compounds areadded to the heavy olefin feedstock.

The OC reactor zone is also a fluidized bed. An example of fluid bedreactor is one of the FCC type used for fluidized-bed catalytic crackingin the oil refinery. The heavy hydrocarbon fraction conversion processis endothermic; therefore, the reaction zone should be adapted to supplyheat as necessary to maintain a suitable reaction temperature.

A part of the catalyst is continuously or intermittently withdrawn fromthe conversion reactor (XTO) and sent to the regeneration zone. Afterthe regeneration, at least a portion of the regenerated catalyst iscontinuously or intermittently sent to the OC reaction zone.Regeneration is carried out by injecting an oxygen-containing streamover the catalyst at sufficient high temperature to burn the depositedcoke on the catalyst.

The OC reactor effluent comprises methane, light olefins, aromatics andhydrocarbons having 4 carbon atoms or more. Advantageously said OCreactor effluent is sent to a fractionator and the light olefins arerecovered. Advantageously at least a part of the hydrocarbons having 4carbon atoms or more are recycled at the inlet of the OC reactor,optionally mixed with the heavy hydrocarbon recovered from the effluentof the XTO reactor. Advantageously, before recycling said hydrocarbonshaving 4 carbon atoms or more at the inlet of the OC reactor, saidhydrocarbons having 4 carbon atoms or more are sent to a secondfractionator to purge the aromatics and heavies. In a preferredembodiment the light olefins recovered from the effluent of the XTOreactor and the light olefins recovered from the fractionator followingthe OC reactor are treated in a common recovery section. Optionally thepurge of aromatics and other heavy hydrocarbons are further submitted tofractionation and at least a part of the toluene and optionally thearomatics having at least 9 carbons are recycled over the OC reactor.

In another embodiment the OC reactor effluent and the XTO reactoreffluent are mixed and sent to a fractionator, or sent to the samefractionator, and the light olefins are recovered. At least a portion ofthe hydrocarbons having 4 carbon atoms or more are recycled at the inletof the OC reactor. Advantageously, before recycling said hydrocarbonshaving 4 carbon atoms or more at the inlet of the OC reactor, saidhydrocarbons having 4 carbon atoms or more are sent to a secondfractionator to purge the aromatics and heavies. The recovered lightolefins are treated in a recovery section which is also called a commonrecovery section as in the above paragraph.

Optionally the purge of aromatics and other heavy hydrocarbons arefurther submitted to fractionation and at least a part of the tolueneand optionally the aromatics having at least 9 carbons are recycled overthe OC reactor.

It is recommended, if the OC reactor feedstock contains dienes, tosubject said feedstock to a selective hydrogenation process in order toremove the dienes.

Advantageously the paraffin's content in the feed at the inlet of the OCreactor is at least 20% weight on carbon basis, preferably at least 30%,more preferably 40%. Advantageously the paraffin's content in the feedat the inlet of the OC reactor is not more than 80% weight.

By doing the XTO and OC reaction is separate reactor zones, allowsoptimising both reactions. As the XTO, OC and regeneration zone arefluidized bed zones, the total pressure is very similar in all threezones. For XTO reaction, the lower the partial pressure of the X and thehigher the reaction temperature, the better is the selectivity for lightolefins. Even at a rather high total pressure the partial pressure of Xcan be minimised by using a diluent like steam. On the other hand, forthe OC reaction, the formation of aromatics is favoured at lowertemperature and at higher partial pressure of olefins, which can benearly as high as the total pressure.

As regards the reactors, e.g. the XTO, and the OC reactors, for certainchemical reactor applications, the fixed bed reactors can have majordisadvantages. When the reaction is fast and highly exothermic orendothermic, hot or cold spots will form in the packed beds anddeteriorate the reactor performance. Sintering, plugging, and fluidmaldistribution can also occur much more readily in packed beds inparticular when coke deposition is rather fast. Comparing to fixed beds,fluidized beds can provide significant advantages when reactions are inparticular highly exothermic or endothermic. Once the solids in the bedare fluidized, the solids inside the bed will behave just like liquid.The gas bubble size, shape, formation, rising velocity, and coalescencein the fluidized beds have quantitative similarity with those of gasbubbles in liquids.

The liquid like behavior of a fluidized bed thus allows the solids to behandled like a fluid, and continuous feeding and withdrawal thereforebecomes possible. The rigorous mixing in a fluidized bed results in auniform temperature even for highly exothermic or endothermic reactionsand provides hence an smoother reactor control. The rigorous mixing alsoimproves solids and fluid contacting, and it enhances heat and masstransfer.

There are many different variations of fluidized beds in practice, whichare covered in available technical handbooks (e.g. Handbook offluidization and fluid-particle system, Taylor&Francis Group LLC, 2003).The fluidization phenomena of gas-solids systems depend very much on thetypes of powders employed. There are several classifications, all basedon the original work by Geldart. Many catalysts, used in fluidized bedsystems are Group A particles, characterized by dense phase expansionafter minimum fluidization and before the beginning of bubbling. Gasbubbles appear at the minimum bubbling velocity.

Fluidization regimes can be classified into two broadcategories-particulate (smooth) and aggregative (bubbling). Inparticulate fluidization, the solid particles usually disperserelatively uniformly in the fluidizing medium with no readilyidentifiable bubbles. Thus the particulate fluidization sometimes isalso called homogeneous fluidization. In the heterogeneous oraggregative fluidization, voids (bubbles) containing no solids areusually formed and are observed in a bubbling fluidized bed or in aslugging bed. For gas-solid systems, there are several distinguishableregimes of fluidization: fixed bed, particulate fluidization, bubblingfluidization, slugging fluidization, and turbulent fluidization for eachof them criteria are available. When the operating velocity is higherthan the transport velocity such that recycle of entrained particles isnecessary to maintain a bed, additional fluidizing regimes are possible.

Particulate Regime: U_(mf)≦U<U_(mb)

For Group A powders, the fixed bed will expand homogeneously(particulate fluidization) above the minimum fluidization velocity(U_(mf)) and no bubbles will be observed as long as the velocity remainsbelow the minimum bubbling velocity (U_(mb)).

Bubbling regime: U_(mb)≦U<U_(ms)

The bubbles appear when the gas velocity is increased beyond the minimumbubbling velocity (Umb). Gas bubbles form above distributor, coalesceand grow. The bubbling regime is characterized by the coexistence of abubble phase and a dense/emulsion phase. The majority of the fluidizinggas is present in the form of bubbles, and as a result, the gas velocitythrough the dense phase is very low.

Slugging Regime: U_(ms)≦U<U_(c)

With large height-to-diameter bed ratios, the bed provides enough timefor bubbles to coalesce into bigger ones. When the bubbles grow toapproximately the size of the bed cross-section, the bed enters theslugging regime with periodic passing of large bubbles and regular largefluctuation of bed pressure drop. The velocity U_(c) corresponds to thebed operating conditions where the slugs reach their maximum diameterand the amplitude of pressure fluctuation is highest.

Transition to Turbulent regime: U_(c)≦U<U_(k)

When the gas velocity is continuously increased beyond this velocityU_(c), large bubbles start to break up into smaller bubbles with smallerpressure fluctuation. This velocity is denoted as U_(k), andcharacterizes the transition from the bubbling regime to the turbulentregime.

Turbulent Regime: U_(k)≦U<U_(tr)

Up to the transport velocity (U_(tr)) the bed is in turbulent regime.Bubbles or voids are still present, although they are lessdistinguishable in the dense suspension. In this regime, interactionsbetween gas voids and the dense/emulsion phase are vigorous and providean effective gas-solid contact.

Fast Fluidized Regime: U>U_(tr)

Beyond the transport velocity (U_(tr)), particles start to be entrainedand continuous operation is no more possible without replacement orrecycling of entrained and carried-over particles. Fast fluidized bedsare typically characterized by a dense phase region at bottom, close tothe distributor coexisting with a dilute phase region on top. Theparticle velocity increases with elevation in the bed and hence the beddensity decreases.

Pneumatic Conveying: U>>U_(tr)

All particles fed to the bottom of the fluidized bed are transported outin dilute phase with concentration varying along the bed height. Atypical example is the riser fluidized bed used in FCC applications.Risers are vertical pipes with a high height-to-diameter ratio (>10) andthe ideal riser approaches plug flow conditions such that both thecatalyst as the fluid phase travels through the riser with minimumbackmixing. Often, minimising backmixing of the fluid phase is essentialfor maximizing selectivity in chemical conversions.

In transport fluidized bed reactors (fast fluidized or pneumaticconveying) core-annulus flow can occur in which a high-velocity, dilutecore is surrounded by a denser, slower-moving annulus. At lowcirculating mass fluxes, the solids in the annulus are flowing downwardat the wall. At high circulating mass fluxes, the solids in the annulusflow up along the wall. This non-uniform flow phenomena will result ininefficient gas-solid contact and non-optimum catalyst performance andsignificant gas and solids backmixing will occur, especially when thereis downflow in the wall region. For a fast fluidization, internals canbe used to redistribute the axial and radial gas-solid flow structure,that is, to improve the uniformity of gas-solid flow structure in spaceand hence promote radial gas-solid exchange. The transport fluidizedreactors required recirculation of catalyst particles back to the bottomof the reactor. This provides the possibility to control the catalystdensity in the fluidized bed by recirculating more or less catalyst.

At the bottom of the fluidized bed, the feed fluid is homogenouslydistributed across the cross-section of the reactor vessel. At the endof the reaction zone, the reaction vapors are separated from theentrained catalyst by means of deflectors, disengagement zone andcyclones. The catalyst is collected, stripped from remaininghydrocarbons and can via standpipes and valves send back to the bottomof the fluidized bed zone.

For the exothermic XTO reaction, it is preferred to have an homogeneoustemperature across (radial and axial) the catalyst bed in order to avoidhot spots and proper control of the catalytic reaction. This can beaccomplished by fast recirculation and eventually backmixing of catalystwithin the reactor vessel. Ways to control the average reactiontemperature are by introducing the feed at a temperature lower than theaverage bed temperature and/or by removing heat from the catalyst bed bymeans of heat exchange. This heat exchange can be accomplished byinternal heat exchange tubes through which a cooling medium flows andtakes heat out of the reactor vessel or by external heat exchange byflowing the hot catalyst, collected from the top of the reactor, aroundheat exchanger tubes and recirculating the cooled catalyst back into thereactor vessel.

For the endothermic OC reaction, an homogeneous temperature across thecatalyst bed is not always preferred as it would require significantoverheating of the feed in order to provide the required reaction heatwhile the catalytic conversion rate would be lower due to thehomogeneous lower temperature of the catalyst bed. A more plug-flow likereactor vessel allows operating the catalyst at a higher averagetemperature and by applying a high catalyst circulation rate allowsintroducing the required reaction heat by entrained hot catalyst. Thishot catalyst can come from a regeneration section where the coke isburned and hence the catalyst absorbs the combustion heat or from theXTO reaction section where the catalyst absorbs the reaction heat fromthe exothermic XTO reaction. During the OC endothermic reaction thecatalyst looses heat and the colder catalyst can be sent back to the MTOzone where again heat is absorbed form the MTO reaction.

As regards the catalyst regeneration, the combined XTO/OC reactor systemhas also a regenerator with primary objective to remove coke depositionson the catalyst by combustion with oxygen. Regenerators are mostlyturbulent or fast fluidized bed systems. Typically, regeneratorcomprises a dens catalyst bed at the bottom of the vessel and a moredilute bed near the top of the vessel. Afterburning is the phenomenonwhen CO reacts with remaining oxygen in the dilute phase or in thefreeboard of the vessel. The combustion of CO releases a lot of heatwhile little catalyst is present that gets overheated, resulting inirreversible deactivation. There are two types of regenerators, eitheroperating in the partial combustion mode or in the total combustionmode. In partial combustion mode, less than stoichiometric amount of airis provided to the regenerator. Most of the carbon is reacted to carbonmonoxide and only part is reacted to carbon dioxide. Ideally, all oxygenshould be consumed and no oxygen should be present in the flue gas. TheCO/CO2 ratio in the flue gas is typically in the range from 0.5 to 2.0.In the total combustion mode, excess air is provided to the regenerator.Ideally, all the carbon in the coke should be reacted to carbon dioxide,and no carbon monoxide should be present in the flue gas. The residualoxygen content in the flue gas is in the range from 1.0 to 3.0 percenton a dry basis. Partial combustion regenerators have several advantagesover total combustion regenerators particularly when the catalyst issensitive to high temperature and steam environment: (i) more coke canbe burned at a given amount of air flow because it requires less thanthe stoichiometric amount of air and (ii) less combustion heat isreleased and hence moderate temperature control is possible whichpreserves better the catalytic activity in the presence of the producedsteam from hydrogen combustion. A potential drawback of the partialcombustion regenerator is higher remaining coke on regenerated catalyst.In case of total combustion regeneration, the remaining carbon oncatalyst is low and catalyst activity restoration is higher. Potentialdrawback of total combustion regenerators includes higher heat releaseowing to total combustion reaction and hence more irreversible catalystactivity loss. Using two-stage regeneration can reduce catalystdeactivation. In the two-stage regeneration, the first stage is operatedat a moderate temperature to burn off mainly the hydrogen, present inthe coke, which has a higher reaction rate, beside some of the carbon.In the second stage, using excess air, the remaining carbon is burned athigher temperature to carbon dioxide and thanks to the absence of watervapor in the second stage regenerator, catalyst deactivation at hightemperature can be minimized.

Afterburning can occur both in partial (breakthrough of oxygen out ofthe dense regenerator bed) and in full combustion mode (breakthrough ofCO out of the dense regenerator bed), most of the time due tomaldistribution of catalyst. Regenerators can be operated at lowtemperature (<650° C.), intermediate temperature (<700° C.) and hightemperature (˜730° C.). At low temperature full combustion is notfeasible, but partial combustion can be operated stable. At intermediatetemperature stable partial combustion is possible and full combustion ispossible, provided combustion promoters are added. High temperatureregeneration can operate stable both in partial as in full combustionmode. Combustion promoters or CO promoters assist to the completeconversion of CO into CO2 in the dense phase of the regenerator andprevents hence temperature excursion due to afterburning. Thesepromoters can improve more uniform combustion of coke, particularly incases of uneven distribution between coked catalyst and air. Combustionpromoters are typically comprised of platinum (300-800 wppm) on aluminacarrier and are added in order to reach 0.5-1.5 ppm of platinum in thecatalyst inventory.

In case of XTO, no extra heat produced during regeneration is requiredfor the XTO reaction as the latter itself is strongly exothermic. On theother hand extra heat can be used in the OC reaction zone, as the OCreaction is endothermic. If more heat is generated in the regenerator,in particular in full combustion mode, than what is required for thereaction, a catalyst cooler can be added to remove the excess heat. Thecatalyst cooler is a heat exchanger that produces steam while removingheat from the catalyst in the regenerator.

Optionally, in order to adjust the propylene and aromatics to ethyleneratio of the whole process (XTO+OC), ethylene in whole or in part can berecycled over the OC reactor and advantageously converted into morepropylene. This ethylene can either come from the separation section ofthe XTO reactor or from the separation section of the OC reactor or fromboth the separation section of the XTO reactor and the separationsection of the OC reactor or even from the optional common recoverysection.

Optionally, in order to adjust the propylene to ethylene ratio of thewhole process (XTO+OC), ethylene in whole or in part can be recycledover the XTO reactor where it combines with the oxygen-containing,halogenide-containing or sulphur-containing organic feedstock to formmore propylene. This ethylene can either come from the separationsection of the XTO reactor or from the separation section of the OCreactor or from both the separation section of the XTO reactor and theseparation section of the OC reactor or even from the optional commonrecovery section.

These ways of operation allow to respond with the same equipment andcatalyst to market propylene to ethylene demand.

FIG. 1 illustrates the general flow of the catalyst between the OCreaction zone, the XTO reaction zone and the regeneration zone. DMEmeans dimethylether. For simplicity of the drawing, the details of eachspecific equipment are not shown.

In the XTO zone (1) the X-containing compound coming via line (2) isconverted into hydrocarbons that flow via line (15) to a depropaniser(20). The deactivated catalyst from the XTO zone goes via line (3) tothe regenerator (4) where it is regenerated by means of combustion.Regenerated catalyst goes back via line (5) to the XTO zone. The OC zone(10) cracks the heavy olefins coming via line (81) into lighter olefinsthat go via line (16) to a depropaniser (70). The catalyst in the OCzone is sent via line (12) to the regenerator (4) for regeneration bymeans of combustion. The regenerated catalyst goes via line (11) back tothe OC zone (10). Catalyst can also go via line (13) from the OC zone(10) to the XTO zone (1) and visa versa via line (14). The depropaniser(20) produces a light fraction that is sent via line (21) to a commondeethaniser (30) and a heavy fraction that is sent via line (22) andline (81) to the OC zone (10). The depropaniser (70) produces a lightfraction that is sent via line (71) to the common deethaniser (30) and aheavy fraction that is sent via line (72) to a rerun column (80). Thererun column (80) produces a C4-C6 fraction that is recycle via line(81) to the OC zone (10) and a C6+ fraction, containing most of thearomatics, that is sent via line (82) to storage. The deethaniser (30)produces a fraction lighter than propylene that is sent via line (31) toa demethaniser (40) and a fraction containing mainly propylene andpropane that is sent via line (32) to a C3-splitter (60). TheC3-splitter (60) produces an overhead propylene product that is sent vialine (61) to storage and a bottom propane product that is sent via line(62) to storage. The overhead (mainly methane and hydrogen) of thedemethaniser (40) is sent via line (41) to a fuel gas system. The bottomproduct of the demethaniser (40) is sent via line (42) to a C2-splitter(50). The C2-splitter (50) produces an overhead ethylene product that issent via line 51 to storage and a bottom ethane product that is sent vialine (52) to storage.

FIG. 2 illustrates a more specific embodiment of a separation section.The products of the XTO zone (1) via line (15) and of the OC zone (10)via line (16) flow to a common depropaniser (70). In this particularcase, all heavy hydrocarbons produced as bottom product of thedepropaniser (70) go via line (72) to the rerun column (80). Theremaining is similar to the explanation of FIG. 1.

As regards the catalyst circulation, in a specific embodiment all thecatalyst from the regenerator is sent to the OC reaction zone, thenfurther sent to the XTO reaction zone and finally all the catalyst ofthe XTO reaction zone is sent to the regenerator (the regeneration zone)and to the OC reaction zone.

FIG. 3 illustrates in a specific embodiment of the flow of the catalystfrom the regeneration zone to the OC reaction zone, then to the XTOreaction zone and finally to the regeneration zone again. For sake ofsimplicity, details of the vessel internals are omitted from thedrawings. Literature and persons skilled in the art easily understandthe requirements of the vessel internals and auxiliary equipment. The X(here methanol/DME) is sent via line (2) into the fluidized bed XTO zone(1). In the top of the XTO zone (1) the products are separated from thecatalyst in the disengagement/cyclone zone (3) and the products are sentvia line 4 to a separation section. Optionally the heat of reactionproduced during the XTO reaction can be extracted by means of a catalystcooler (5). The XTO zone receives the catalyst via line (14) from the OCzone (10). The C4+ hydrocarbons and eventually ethylene is injected intothe OC zone (10) via line (11). The catalyst, reactants and producttravel to the disengagement/cyclone zone (12) where the products areseparated from the catalyst. The products are sent to a separationsection via line (13). The catalyst is withdrawn from thedisengagement/cyclone zone (12) via line (14) to the XTO zone (1). Thedeactivated catalyst from the XTO zone (1) is withdrawn via line (6) tothe regeneration zone (20). Air is injected via line (21) into theregeneration zone (20) where the coke deposits are burned. In thedisengagement/cyclone zone (22), the combustion gases are separated fromthe catalyst and the combustion gases sent out via line (23).Optionally, as the combustion of coke deposits is very exothermicreaction and the temperature of the regeneration zone (20) need carefulcontrol, a catalyst cooler (24) can be installed through which the hotcatalyst circulates in order to be cooled down which allows to controlthe temperature in the regeneration zone (20). The regenerated catalystis sent via line (25) to the OC zone (10).

FIG. 4 illustrates a more specific embodiment of FIG. 3. At least ofpart of the catalyst present in the XTO zone (1) and separated from theproducts in the disengagement/cyclone zone (3) is sent via line (7)together with the fresh regenerated catalyst via line (25) to the OCzone (10). The remaining is similar to FIG. 3.

FIG. 5 illustrates an embodiment where a common disengagement/cyclonezone for products and catalyst is used for the XTO and OC zone. Thecommon disengagement/cyclone zone (3) is located at the top of the XTOzone (1). The end of the OC zone (10) is connected to thedisengagement/cyclone zone (3) where the catalyst is separated from theproducts produced in the XTO (1) and OC (10) zones and sent via line 4to a separation section. The regenerated catalyst is sent via line (25)from the regeneration zone (20) to the OC zone (10). The catalyst fromthe OC zone (10) is mixed with the catalyst entrained from the XTO zone(1) and separated from product in the common disengagement/cyclone zone(3) and flows back to the XTO zone via line (5) (which can consistoptionally of a catalyst cooler as well). Part of this deactivatedcatalyst is sent via line (6) to the regeneration zone (20).

FIG. 6 illustrates a more specific embodiment of FIG. 5 where thedisengagement/cyclone zone is on the top of the OC zone (10).Regenerated catalyst is sent via line (25) from the regeneration zone(20) to the OC zone (10). At least a part of the catalyst in the OC zone(10) is sent via line 14 to the XTO zone (1). The catalyst and productsfrom the XTO zone (1) flow to the common disengagement/cyclone zone (12)where they are mixed with the products and catalyst coming from the OCzone (10). Catalyst, separated in the disengagement/cyclone zone (12),is sent via line (15) to the regeneration zone (20). The mixed productsare sent via line 13 to a separation section.

The method of making the olefin products from an oxygenate feedstock caninclude the additional step of making the oxygenate feedstock fromhydrocarbons such as oil, coal, tar sand, shale, biomass, waste andnatural gas. Methods for making oxygenate feedstocks are known in theart. These methods include fermentation to alcohol or ether, makingsynthesis gas, then converting the synthesis gas to alcohol or ether.Synthesis gas can be produced by known processes such as steamreforming, autothermal reforming and partial oxidation in case of gasfeedstocks or by reforming or gasification using oxygen and steam incase of solid (coal, organic waste) or liquid feedstocks. Methanol,methylsulfide and methylhalides can be produced by oxidation of methanewith the help of dioxygen, sulphur or halides in the correspondingoxygen-containing, halogenide-containing or sulphur-containing organiccompound.

One skilled in the art will also appreciate that the olefin productsmade by the oxygenate-to-olefin conversion reaction using the molecularsieve of the present invention can be polymerized optionally with one ormore comonomers to form polyolefins, particularly polyethylenes andpolypropylenes. The present invention relates also to said polyethylenesand polypropylenes.

EXAMPLES Example 1

A sample of phosphated ZSM-5 prepared according to an adapted examplefrom EP2025402A1 from HZSM-5 (Si/Al=13) synthesized without template wasextruded with low sodium silica sol, phosphated xonotlite (Ca/P˜1) and2-3% of extrusion additives. The resulted catalyst contained about 40 wt% of zeolite. The dried extruded catalyst was washed with water solutionat room temperature followed by drying at 110° C. for 16h andcalcinations at 700° C. for 2h.

Example 2 MTO

Catalyst test was performed in a down flow fixed bed reactor on 0.5 g(35-45 meshes) of sample described in the example 1. Prior to catalyticrun the catalyst was heated in flowing N2 (5 NI/h) up to the reactiontemperature. The pure MeOH was fed to the catalyst at 550° C., WHSV(CH₃OH)=5.7h⁻¹, P=1,5 bara. Analysis of the products has been performedon-line by a gas chromatograph equipped with a capillary column.

The catalyst showed stable performance and substantially full methanolconversion. The results of the average catalyst performance during thefirst 5 h on stream on carbon basis, coke free basis are in table 1hereunder in which BTX means benzene-toluene-xylene.

TABLE 1 Product wt % C2- 6.8 C3- 42.8 BTX 2.2

Example 3 OC Reaction to Produce Aromatics

Catalyst tests were performed in a fixed bed reactor down flowstainless-steel reactor (8 mm diameter) with a blended feed of 70 w puremethanol with 30 w 1-butene. The values of weight hour's space velocity(WHSV_C) given in the tables 2-4 are calculated as weight of CH₂/(weightof catalyst x hour). The experiments at different space velocities wereperformed by varying the mass of catalyst loaded (catalyst from exampleI) at constant mass flow of (CH3OH+1-butene) into the reactor.

Prior to catalytic run the catalyst was heated in flowing N₂ (5 NI/h) upto the reaction temperature. Analysis of the products has been performedon-line by a gas chromatograph equipped with a capillary column.

Catalytic performance of catalyst was measured at substantially fullmethanol conversion. The results are given on carbon basis, coke freebasis.

TABLE 2 M catalyst, g 1.6 1.6 1.6 WHSV_C, h−1 1 1 1 T, ° C. 550 550 550P, bara 0.8 1.3 1.8 Diluent He non non BTX 2.8 6.5 12.7

The results given above illustrate the effect of partial pressure toaromatic production. An increase of hydrocarbon partial pressure(CH3OH+1-butene) from 0.8 to 1.8 bars leads to significantly higheraromatic production.

TABLE 3 M catalyst, g 1.6 1.45 0.22 WHSV_C, h−1 1 2.2 14.2 T, ° C. 550550 550 P, bara 1.5 1.5 1.5 BTX 8.5 4.5 0.9

The results given above illustrate the effect of space velocity toaromatic production. Lower space velocity favours to higher aromaticmaking.

TABLE 4 M catalyst, g 0.22 0.22 WHSV_C, h−1 14.2 14.2 T, ° C. 500 550 P,bara 1.5 1.5 BTX 1.9 0.9

The results given above illustrate the effect of temperature to aromaticproduction. Lower temperature favours to higher aromatic making.

TABLE 5 FEED 1-butene + CH3OH 1-butene ratio 30/70 pure M catalyst, g0.22 0.25 WHSV_C, h⁻¹ 14.2 14.1 T, ° C. 550 550 P, bara 1.5 1.5 BTX 0.94.5

The results given above demonstrate higher yield of BTX in case ofreaction of pure 1-butene in respect to the blended feed of1-butene+CH₃OH under equal conditions.

1-20. (canceled)
 21. A process of making light olefins and aromatics, ina combined organics to olefins (XTO)-olefins conversion (OC) process,from an oxygen-containing, halogenide-containing or sulphur-containingorganic feedstock comprising: selecting a molecular sieve having poresof 10- or more-membered rings; contacting the molecular sieve with ametal silicate comprising at least one alkaline earth metal to form acatalyst composite comprising at least 0.1 wt % of silicate; providing afirst portion of an oxygen-containing, halogenide-containing, orsulphur-containing organic feedstock; providing an XTO reaction zone, anOC reaction zone and a catalyst regeneration zone, wherein one or morecatalysts are in the XTO reaction zone and the same one or morecatalysts are in the OC reaction zone, wherein each of the one or morecatalysts is a molecular sieve containing at least 10 membered ringspore opening in their microporous structure, wherein at least one of thecatalysts comprises the catalyst composite; wherein each of the one ormore catalysts circulates in the three zones, such that at least aportion of the regenerated one or more catalysts are passed to the OCreaction zone, at least a portion of the one or more catalysts in the OCreaction zone are passed to the XTO reaction zone and at least a portionof the one or more catalysts in the XTO reaction zone are passed to theregeneration zone; contacting the first portion of theoxygen-containing, halogenide-containing or sulphur-containing organicfeedstock in the XTO reactor with the one or more catalysts atconditions effective to convert at least a portion of the feedstock toform a XTO reactor effluent comprising light olefins and a heavyhydrocarbon fraction; separating the light olefins from the heavyhydrocarbon fraction; and contacting the heavy hydrocarbon fraction andoptionally a second portion of the oxygen-containing,halogenide-containing or sulphur-containing organic feedstock in the OCreactor with the one or more catalysts at conditions effective toconvert at least a portion of the heavy hydrocarbon fraction and theoxygen-containing, halogenide-containing or sulphur-containing organicfeedstock to light olefins and aromatics.
 22. The process of claim 21,wherein the second portion of the oxygen-containing,halogenide-containing or sulphur-containing organic feedstock is up to70 wt % of the total oxygen-containing, halogenide-containing orsulphur-containing organic feedstock.
 23. The process of claim 21,wherein the second portion of the oxygen-containing,halogenide-containing or sulphur-containing organic feedstock is 0 wt %of the total oxygen-containing, halogenide-containing orsulphur-containing organic feedstock.
 24. The process of claim 21,wherein the catalyst composite comprises from 10 to 90 wt % of themolecular sieve.
 25. The process of claim 21, the molecular sieve isselected from a group consisting of MFI, MOR, MEL, clinoptilolite, FER,FAU, MWW, BETA, ZSM-21, ZSM-22, ZSM-23, ZSM-42, ZSM-57, LTL, andmixtures of thereof.
 26. The process of claim 21, the molecular sieve isa zeolite, and wherein phosphorus is introduced to the zeolite before,simultaneously or after blending of the molecular sieve with the metalsilicate.
 27. The process of claim 21, wherein the molecular sieve hasan initial atomic ratio Si/Al of at least 4 and not greater than 500.28. The process of claim 21, wherein the molecular sieve is dealuminatedand then modified with phosphorous before or during contact with themetal silicate.
 29. The process of claim 21, wherein the catalystcomposite comprises metal phosphates.
 30. The process of claim 21,wherein the metal silicate includes at least one alkaline earth metal.31. The process of claim 21, wherein the metal silicate includes a metalthat is Ga, Al, Ce, In, Cs, Sc, Sn, Li, Zn, Co, Mo, Mn, Ni, Fe, Cu, Cr,Ti or V.
 32. The process of claim 21, wherein silicate anion is presentin the metal silicate as SiO₃ ²⁻, SiO₄ ⁴⁻, Si₂O₇ ⁶⁻, or Si₃O₁₀ ^(8.) 33.The process of claim 21, wherein the metal silicate is a calciumsilicate.
 34. The process of claim 21, wherein, prior to contacting themolecular sieve with the metal silicate, the molecular sieve is modifiedby at least one of: steaming, leaching, washing, drying, calcining,impregnation and ion-exchange.
 35. The process of claim 21, wherein,prior to contacting the molecular sieve with the metal silicate, themetal silicate is modified by at least one of: calcining, steaming,ion-exchange, impregnation, and phosphatation.
 36. The process of claim21, wherein all of the one or more catalysts from the catalystregeneration zone is sent to the OC reaction zone, then further sent tothe XTO reaction zone and finally all the catalyst of the XTO reactionzone is sent to the catalyst regeneration zone.
 37. The process of claim21, wherein all of the one or more catalysts from the catalystregeneration zone is sent to the OC reaction zone, then further sent tothe XTO reaction zone and finally at least a portion of the one or morecatalysts of the XTO reaction zone is sent to the catalyst regenerationzone and the remaining portion of the one or more catalysts is sent tothe OC reaction zone.
 38. The process of claim 21, wherein all of theone or more catalysts from the catalyst regeneration zone is sent to theOC reaction zone, at least part of the one or more catalysts from the OCreaction zone is further sent to the XTO reaction zone and the remainingpart of the one or more catalysts is sent to the catalyst regenerationzone and all of the one or more catalysts from the XTO reaction zone issent to the OC reaction zone.
 39. The process of claim 21, whereinpartial pressure of olefins in the OC reactor ranges from 0.5 to 10bars.
 40. The process of claim 21, wherein a temperature of the OCreactor ranges from 350 to 600° C.